KR19980024238A - Exposure device - Google Patents

Abstract

The illumination accuracy of the illuminance sensor provided in the exposure apparatus is increased and the processing speed of the calibration data is increased.

An integrator sensor 18 for detecting the illuminance of the exposure light IL divided in the illumination system 17 beam-splitter 33, and a fixed illumination sensor 7 fixed on the wafer stage 1, The roughness meter 2 is detachably mounted on the wafer stage 1 and an output signal from the detachable illumination system 2 is supplied to the roughness control unit 12 via the sensor control device 3 or the like. For example, at the time of calibrating the integrator sensor 18, the illuminance of the exposure light IL is measured synchronously (synchronously) by the integrator sensor 18 and the detachable illuminometer 2, and the output signal from the illuminator is measured in the illuminance control unit 12 do.

Description

Exposure device

The present invention relates to an exposure apparatus used for exposing a pattern on a mask to a photosensitive substrate in a photolithography process for manufacturing semiconductor devices, liquid crystal display devices, image pickup devices (CCDs, etc.), thin film magnetic heads, And more particularly to an exposure apparatus having a function of calibrating a permanent illuminance sensor so as to directly or indirectly measure an exposure light illuminance on a stage on which a photosensitive substrate is disposed.

Conventionally, for example, there has been known a batch exposure type exposure apparatus for transferring a pattern of a reticle (or a photomask or the like) as a mask onto a wafer (or a glass plate or the like) coated with a photoresist as a photosensitive substrate through a projection optical system An exposure apparatus such as a projection exposure apparatus (stage or the like), or a proximity type exposure apparatus that transfers a pattern of a reticle directly onto a wafer without passing through a projection optical system is used. Recently, in order to increase the exposure area substantially without increasing the size of the projection optical system, the reticle and the wafer are synchronously scanned with respect to the projection optical system so that the reticle pattern is sequentially transferred to each shot area on the wafer, A scanning exposure type projection exposure apparatus such as a system is also being used.

In general, a proper amount of exposure is determined for the photoresist on the wafer. Therefore, such an exposure apparatus is provided with an illuminance sensor for directly or indirectly measuring the illuminance of the exposure light on the wafer, and controls the exposure amount on the wafer based on the meter of this illuminance sensor.

12 shows a projection exposure apparatus equipped with a conventional illumination sensor. In FIG. 12, the exposure light IL emitted from the exposure light source 109 passes through the illumination system 103 to illuminate the pattern area of the reticle R, and under the exposure light IL, Is transferred to each shot area on the wafer W coated with the photoresist through the projection optical system 102. [ The wafer W is protected and supported on the wafer stage 101 for three-dimensionally positioning the wafer.

The illumination system 103 includes a fly-eye lens, a beam splitter 111 for separating a part of the exposure light emitted from the fly-eye lens, and a condenser lens. The exposure light IL separated from the beam splitter 111 is incident on an illuminance sensor And the output signal of the integrator sensor 110 is supplied to the illuminance control unit 105. The illuminance control unit 105 receives the output signal of the integrator sensor 110, The illuminance control unit 105 is connected to a main controller 107 for controlling the operation of the entire apparatus, and the main controller 107 is connected to a console 112 composed of an input device or a display.

The beam splitter 111 has a constant reflectance and can calculate the amount of light transmitted through the beam splitter 111 and directed to the wafer W based on the illuminance detected by the integrator sensor 110. However, in practice, it is necessary to consider the amount of light due to reflection and absorption in the reticle R, the projection optical system 102, and the like. Therefore, as described later, the ratio of the output value of the integrator sensor 110 to the output value of the illuminance sensor provided on the wafer stage 101 is obtained and stored in the main controller 107. In the main controller 107 during exposure, The illuminance of the exposure light on the wafer W is obtained from the output value of the integrator sensor 110 and the exposure amount for the wafer W is controlled based on the illuminance.

An illuminance sensor 104, which is a permanent photoelectric detector dedicated to the apparatus, is fixed on the wafer stage 101 in the vicinity of the wafer W, and the output signal of the illuminance sensor 104 is supplied to the illuminance control unit 105 through the signal cable 106. Then, for example, before the exposure, the light receiving portion of the illumination sensor 104 is set in the exposure field of the projection optical system 102, and if necessary, the exposure light and the illumination irregularity on the wafer stage 101 are measured.

In this case, since a plurality of exposure apparatuses are provided in a production line for semiconductor devices and the like, it is necessary to match the exposure amounts given to the wafers in the respective exposure apparatuses. In order to do this, It is necessary to calibrate the output (sensitivity) with respect to the incident light amount of the laser sensor 110 and the illuminance sensor 104 or the like. That is, the appropriate exposure amount for the photoresist is determined from the exposure time and the illuminance of the image having the highest resolution, for example, in the image displayed by the exposure of the exposed wafer by varying the exposure time in various ways under a certain degree. Therefore, if the sensitivity of the illuminance sensor is different for each of the exposure apparatuses, the appropriate exposure amount varies for each exposure apparatus due to the difference in sensitivity. In order to calibrate the sensitivities of the integrator sensor 110 and the illuminance sensor 104, a detachable illuminometer 108, which is conventionally a standard, is used.

That is, the illuminometer 108 is detachable from the wafer stage 101 for matching with another exposure apparatus, and is movable on the wafer stage 101. The output signal of the illuminometer 108 is supplied to the display unit 113 through the signal cable 114, An instrument of the light meter 108 is displayed at 113. In this case, the display unit 113 is provided outside the chamber in which the projection exposure apparatus shown in Fig. 12 is stored so that the operator can easily see the display contents. Since the illuminometer 108 can be detached from the wafer stage 101, sensitivity calibration of the integrator sensor 110 and the illuminance sensor 104 is performed using the illuminometer 108 as follows. As a result, when a given exposure dose (dose, dose) is given to the photoresist on the wafer in an arbitrary exposure apparatus, the same exposure dose can be given to other exposure apparatuses.

When the sensitivity of the integrator sensor 110 and the illuminance sensor 104 is corrected in the projection exposure apparatus of Fig. 13, the illuminance meter 108 is provided at a predetermined position on the wafer stage 101, and the illuminometer 108 is placed near the center of the exposure field of the projection optical system 102 After moving, the exposure and circle 109 are turned on based on an instruction from the main controller 107, and the illuminance on the wafer stage 101 is measured by the illuminometer 109. The output value IA of the light illuminometer 108 is displayed on the display 113 and recorded by the operator.

Then, the permanent illuminance sensor 104 fixed on the wafer stage 101 is moved to the vicinity of the center of the exposure field of the projection optical system 102, and the illuminance is measured. The output value IB of the illuminance sensor 104 is subjected to analog / digital (A / D) conversion in the luminance control element 105, and the measurement data after the A / D conversion is supplied to the main controller 107. The output value IC of the permanent integrated sensor 110 is also sampled in the illumination control unit 105 and supplied to the main controller 107 in parallel with this. The output value IB of the illuminance sensor 104 and the output value IC of the integrator sensor 112 supplied to the main controller 107 are transmitted from the main controller 107 to the console 112 and the output values IB and IC are displayed on the display of the console 112. [

Assuming here that the output of the exposure light source 109 is constant, the operator obtains the value K _AC (= IA / IC) of the output value IC of the integrator sensor 110 with respect to the output value IA of the illuminometer 108. The value K _AC of this ratio becomes a parameter for calibration of the integrator sensor 110. That is, the output value of the integrator sensor 110 at the time of exposure is multiplied by the parameter K _AC , and the actual illuminance of the wafer W corresponding to the other exposure apparatus can be calculated. The ratio K _AB of the output value IB of the illuminance sensor 104 to the output value IA of the illuminance sensor 108 is a parameter for calibration of the illuminance sensor 104. That is, the output value of the illuminance sensor 104 is multiplied by the parameter K _AC , and the illuminance corresponding to the other exposure apparatus is calculated.

As described above, since the timing at which the output value of the standard illuminometer 108 is read from the display unit 113 and the timing at which the output value of the illuminance sensor 104 and the integrator sensor 110 are measured via the console 112 are different from each other, If there is a time interval in the output, the measured parameters K _AC and K _AB change as described above. Therefore, conventionally, in order to alleviate the influence of this fluctuation, the output values IA, IB, IC of the illuminance meter 108 and the like are measured and averaged for a long time, or a peak hold value Respectively, and the parameters K _AC and K _AB are calculated. However, there is a problem in that the measurement accuracy of the obtained parameters can not be increased so much because the intervals between the timing of the measurement of the output value IA and the timing of the measurement of the output values IB, IC are not small.

Since the display 113 of the output value IA of the reference illuminometer 108 and the console 112 that displays the output values of the illuminance sensor 104 and the integrator sensor 110 are managed separately and independent of each other, There is a problem that calculation of _AC and K _AB takes time.

When a plurality of exposure apparatuses are used in parallel, a plurality of standard illuminance meters 108 may be prepared and calibrated in parallel for the respective illumination apparatuses of the respective exposure apparatuses. In this case, if the degree of matching of the outputs between the illuminance meters 108 is poor, there is a problem that the degree of matching of the illuminance between the respective exposure apparatuses also decreases.

It is a first object of the present invention to provide an exposure apparatus capable of high-precision calibration of a prepared illuminance sensor and high-speed processing of measurement data for calibration, in view of this point.

It is a second object of the present invention to provide an exposure apparatus capable of increasing the degree of matching during roughness measurement between exposure apparatuses by accurately calibrating a standard illuminance sensor.

1 is a schematic structural view showing a first embodiment of an exposure apparatus according to the present invention.

FIG. 2A is an enlarged view showing a state in which the removable illuminometer 2 of FIG. 1 is mounted on the wafer stage 1, FIG. 2B is a plan view of FIG. 2A, and FIG. 2C is an enlarged view showing a detachable illuminometer 2 A of a cordless system.

FIG. 3 is a view for explaining a method for obtaining the position of the removable illuminometer 2 of FIG. 1. FIG.

Fig. 4 is a configuration diagram showing the illumination system 17 of Fig. 1 in detail.

FIG. 5A is a plan view showing a method of measuring the illuminance in the exposure field by the removable illuminometer 2 of FIG. 1, and FIG. 5B is a top view of a method of measuring illuminance in the exposure field by the fixed illuminance sensor 7 of FIG.

FIG. 6A is a plan view showing an example of an aperture stop provided on the exit surface of a flyeye lens in the illumination system 17 of the projection exposure apparatus of FIG. 4, and FIG. 6B is a plan view of the aperture stop, R, and Fig. 6C is a diagram showing a state in which exposure light of a large aperture angle is incident on the reticle R. Fig.

FIG. 7A is an explanatory diagram of a method of calculating a calibration parameter in a stepper type projection exposure apparatus, and FIG. 7B is an explanatory diagram of a calculation method of a calibration parameter in a scanning exposure type projection exposure apparatus.

8 is a schematic structural view showing a projection exposure apparatus according to a second embodiment of the present invention.

Fig. 9 is a diagram showing pulse emission timings using the excimer laser light source of Fig. 8, and measurement timings of an integrator sensor and the like at that time.

FIG. 10A is a diagram showing a hierarchical structure for managing the reference illuminance sensor in the embodiment of the present invention, FIG. 10B is a diagram showing a linear function for calibration among the reference illuminance sensors in FIG. 10A, And a non-linear function for calibration between illuminance sensors.

FIG. 11A is a view showing an example of a calibration jig for calibrating a reference illuminance sensor in an embodiment of the present invention, and FIG. 11B is a view showing another example of the calibration jig.

12 is a schematic configuration diagram showing a projection exposure apparatus equipped with a conventional illuminance sensor.

Description of the Related Art [0002]

R: Reticle W: Wafer

1: wafer stage 2: detachable illuminometer

3: Sensor control device 4, 5: Signal cable

6: connector 7: fixed illuminance sensor

10: projection optical system 11: connector

12: Illumination control element 13: Storage device

14: Console 15: Light source control unit

16: light source unit 17: illumination system

18: integrator sensor 20: temperature control element

23: power supply unit 25: light source conversion unit

40: excimer laser light source 41: laser control device

42: Sensing section control system 44, 45: Calibration jig

50: main controller 52A-52D: aperture stop

58, 62: beam splitter 59: signal processing system

60: Host computer

1, the first exposure apparatus according to the present invention is provided with a substrate stage 1 for positioning a photosensitive substrate W, and is provided with a mask stage R for exposure under illumination light IL for exposure, An exposure apparatus for transferring and exposing a formed pattern onto a photosensitive substrate W on a substrate stage 1 is provided with an exposure apparatus which is detachable on a substrate stage 1 and directly measures the illuminance of the illumination light IL on the substrate stage 1 A permanent illuminance sensor 7 or 18 for directly or indirectly measuring the illuminance of the illumination light IL on the substrate stage 1 and a light intensity sensor 2 for inputting measurement data of the detachable lightness sensor 2 And an exposure amount control means (12, 13) for storing the relationship between the measurement data of the detachable illuminance sensor (2) inputted through this interface device and the measurement data of the permanent illuminance sensors (7, 18) 50).

According to the first exposure apparatus of the present invention, the measurement data is directly input from the detachable light intensity sensor 2 through the interface devices 3-6 and 11, and substantially simultaneously with the measurement data from the permanent light intensity sensors 7 and 18 The measurement data is also input and the relationship between the measurement data of the detachable illuminance sensor 2 and the measurement data of the permanent illuminance sensors 7 and 18, that is, the ratio of the measurement data, or the offset, is obtained. This means that calibration of the measurement data of the permanent illuminance sensors 7, 18 is performed. At this time, since the measurement data of the detachable ambient light sensor 2 and the permanent illuminance sensors 7 and 18 are inputted at almost the same time, the light source of the illumination light IL for exposure is not affected by the output time fluctuation, The relationship between the measurement data of the two illuminance sensors can be accurately obtained even if there is an output fluctuation or an irregularity of the excimer laser light source, and the calibration of the permanent illuminance sensors 7, 18 is performed to a high degree.

Further, since the measurement data of the two illuminance sensors are commonly input to the exposure amount control means 12, 50 and processed at a high speed on-line, the calibration of the permanent illuminance sensors 7, 18 is performed at a high speed. In addition, an input error due to an operator's intervention or the like does not occur.

In this case, one example of the permanent illuminance sensor includes an indirect illuminance sensor 18 that indirectly measures the illuminance of the illumination light IL on the substrate stage 1 by detecting the illuminance of the light beam separated from the illumination light IL. In which case the exposure amount control means 12 and 50 receive the measurement data of the detachable illuminance sensor 2 via the interface devices 3-6 and 11 and the measurement of the permanent illuminance sensor 18 It is desirable to input data. The indirect illumination sensor 18 refers to an integrator sensor that detects the illuminance of a light beam (light beam) divided from the illumination light IL. The indirect illumination sensor 18 measures the measurement data of the integrator sensor and the removable illuminance sensor 2 synchronously The influence of the fluctuation of the output time of the light source for exposure is eliminated, and the calibration of the integrator sensor is performed with high accuracy.

In the case where the illumination light IL for exposure is pulsed light, the exposure control means 12 and 50 synchronize with the pulse light emission of the illumination light IL for exposure via the interface devices 3-6 and 11, It is preferable to input the measurement data of the measurement unit 2. This makes it possible to calibrate the permanent illuminance sensors 7 and 18 with high precision with respect to the detachable illuminance sensor 2 even if there is irregularity of the pulse energy without deviating from the measurement timing of the two illuminance sensors.

1 and 2C, the interface devices 3, 5, 6, 11 supply measurement data of the detachable light intensity sensor 2A to the exposure amount control means 12, 50 in a cordless manner . Usually, the exposure apparatus is accommodated in a chamber in which temperature control is performed. However, in the cordless type, handling of the detachable light intensity sensor 2A is facilitated since a compartment or a wiring to be connected is unnecessary.

2 and 10, the second exposure apparatus according to the present invention is provided with a substrate stage 1 for positioning the photosensitive substrate W, In the exposure apparatus for transferring and exposing the pattern formed on the mask R onto the photosensitive substrate W on the substrate stage 1 under the irradiation condition IL of the substrate stage 1, the illuminance of the illumination light IL on the substrate stage 1 is directly or indirectly And a controller for controlling the illuminance of the illumination light IL on the substrate stage 1 in order to perform output calibration of the permanent illuminance sensors 7 and 18, (Including the value of a ratio, etc.) of the output of the first detachable light intensity sensor 2 to the output of the second detachable light intensity sensor A1 as a predetermined reference And a storage means 25 for storing the data.

According to the second exposure apparatus of the present invention, the second detachable illuminance sensor A1 serves as a mother machine for the first illuminance sensor 2, and the management of the absolute illuminance is controlled by a mosquito, ), And Son-gi (孫 機). For example, when a plurality of exposure apparatuses are used in parallel, a large number of detachable light intensity sensors 2 as a reference are required. At this time, when the output linearity with respect to the incident light quantity of the first wavelength A1 is set as an absolute reference, by correcting the output of the magnetic wave 2 with the correction value of the output of the first wavelength, the degree of matching of the illuminance meters .

The third exposure apparatus according to the present invention has a substrate stage 1 for positioning the photosensitive substrate W as shown in Figs. 1 and 11, for example. R for transferring and exposing the pattern formed on the substrate stage 1 to the photosensitive substrate W on the substrate stage 1. The exposure apparatus includes a permanent illuminance sensor 7 for directly or indirectly measuring the illuminance of the illumination light IL on the substrate stage 1, A first detachable roughness detector 18 for directly measuring the illuminance of the illumination light IL on the substrate stage 1 in order to calibrate the output of the permanent illuminance sensors 7 and 18 and detachable on the substrate stage 1, A second detachable illuminance sensor A1 serving as an output reference of the first detachable illuminance sensor and an illumination light IL for exposure on the substrate stage 1 are divided into a first detachable illuminance sensor 1, (61, 62, 63A, 63B) for guiding the light to the first and second detachable rough surfaces (2, A1) Standing and a signal processing unit 59 for comparison to the output of (2, A1) in parallel.

According to the third exposure apparatus of the present invention, the illuminance of the illumination light IL divided by the division optical system on the substrate stage 1 is measured by the first and second detachable light intensity sensors 2 and A1, The illuminance sensor 2 can be calibrated, so that the first detachable illuminance sensor 2 is calibrated with high accuracy without any influence of the shaking of the illuminating light IL and the optical system in the middle. In other words, calibration of the illuminance sensor 2 as magnetism is performed with respect to the illuminance sensor A1 as a human being. Then, the permanent illuminance sensors 7 and 18 are calibrated with high accuracy by the first detachable illuminance sensor 2 which is calibrated with high accuracy. This improves the accuracy of illumination matching between exposure apparatuses.

[Example]

Hereinafter, a first embodiment of an exposure apparatus according to the present invention will be described with reference to Figs. 1 to 7. Fig. The present invention can be applied to any exposure apparatus such as a stepper type or a step-and-scan type. However, the following embodiments apply the present invention to a step-type projection exposure apparatus.

1 shows a schematic configuration of a projection exposure apparatus according to this embodiment. In FIG. 1, a photosensitive exposure light IL is emitted from a light source unit 16 including an exposure light source made of a mercury lamp, a shutter, and the like to the photoresist of the wafer. The main controller 50 for controlling the operation of the entire apparatus is controlled through the light source control unit 15 and the output of the exposure light source in the light source unit 16 is also controlled by the light source control unit 15, The exposure amount of one shot is controlled by the output of the light source and the opening / closing of the shutter. As the exposure light IL, a bright line such as a g line of i-line (wavelength 365 nm) or less of a mercury lamp can be used. As other exposure light sources, an ArF excimer laser light source, a KrF excimer laser light source, a copper vapor laser light source, a YAG laser high frequency generating device, or the like can be used.

The exposure light IL emitted from the light source unit 16 enters the illumination system 17.

4 is a configuration diagram showing the internal configuration of the illumination system 17. As shown in Fig. 4, the exposure light IL incident on the illumination system 17 is incident on the fly-eye lens 31 as an optical integrator. A secondary light source is formed on each emission surface of each lens element of the fly's eye lens 31, and the surface light surface is formed by these secondary light sources. A plurality of aperture diaphragms are arranged on the exit surface of the fly-eye lens 31, that is, the pupil plane of the illumination system 17, as conversion materials for adjusting the size and phenomenon of the surface light source. These aperture stops are fixed to the turret-shaped disk 30, and the disk 30 is rotated by the main controller 50 through the driving device 50A, whereby a desired aperture stop can be set on the exit surface of the fly-eye lens 31. [

6A shows the arrangement of the aperture stop on the disk 30 of FIG. 4. In FIG. 6A, six aperture stops 52A-52F are fixed at an equal interval around the center of the disk 30. FIG. The first aperture stop 52A has a circular aperture used when illuminating with an intermediate coherence factor, and the second aperture stop 52B and the third aperture stop 52C have a band aperture And a conventional opening for band illumination. The fourth aperture stop 52D is a circular aperture used for normal illumination, and the fifth aperture stop 52E has four small aperture apertures in the periphery. Called aperture stop for deformed illumination. The sixth aperture stop 52F has a small circular aperture used when illuminating with a small sigma value.

Returning to Fig. 4, the first aperture stop 52A is disposed on the exit surface of the fly-eye lens 31. [ The exposure light IL having passed through the first aperture stop 52A is incident on the beam spiller 33. [ The beam splitter 33 transmits most of the incident light flux and reflects the rest. A certain proportion of the light flux in the exposure light IL is reflected in a direction substantially orthogonal to the incident light path of the exposure light IL from the beam splitter 33. The reflected light beam is incident on the integrator sensor 18 made of a photodiode through the condenser lens 43 do.

On the other hand, the exposure light IL transmitted through the beam splitter 33 is condensed on the aperture of the variable visual field stop (reticle blind) 28 through the first relay lens 29, and the illumination range on the reticle of the exposure light IL by the variable visual- . The opening shape and size of the variable field stop 28 are set by the main controller 50 through the driving device 50B. The exposure light IL having passed through the variable field stop 28 passes through the second relay lens 27 and the condenser lens 26 and is irradiated to the pattern area of the reticle R. [

1, the pattern image of the reticle R under the exposure light IL is projected through the projection optical system 10 at a projection magnification? (For example, 1/4, 1/5, etc.) / RTI > Hereinafter, the Z axis is taken parallel to the optical axis AX of the projection optical system 10, and the X axis is taken parallel to the plane of Fig. 1 and the Y axis is taken perpendicular to the plane of Fig. 1 in a plane perpendicular to the Z axis. In this case, the photoelectric signal from the integrator sensor 18 that has received the light flux from the illumination system 17 is supplied to the illumination control unit 12 and converted into analog / digital (A / D) by the illumination control unit 12. The roughness information of the current exposure light IL is directly sent from the roughness control unit 12 to the main controller 50 and the light source control unit 15 on the basis of the A / D converted digital data. In the light source control unit 15, And the output of the exposure light source in the light source unit 16 is controlled so as to be illuminance. Further, in the main controller 50, the relationship between the output of the integrator sensor 18 and the exposure light intensity on the wafer W is stored in advance, and the illuminance on the wafer W is calculated from this relationship. The opening and closing operation of the light source unit 16 is controlled through the light source control unit 15 so as to obtain an appropriate integrated exposure amount for the W-phase photoresist.

When the exposure light source is a pulsed light source such as an excimer laser light source and is of a batch exposure type such as a stepper, the shutter opening / closing operation in the light source unit 16, the control of the photosensitive mechanism provided in the light source unit 16, The control of the integrated exposure amount is performed. On the other hand, when the exposure light source is a pulse light source and is of the scanning exposure type such as the step-and-scan method, the light intensity of the exposure light is controlled by the photosensitive mechanism provided in the light source unit 16, The integrated exposure amount can be controlled.

In Fig. 1, the reticle R lies on a reticle stage (not shown) that is fine in the X direction, the Y direction, and the rotational direction. The position of the reticle stage is accurately measured by a laser interferometer (not shown) provided outside, and the main controller 50 determines the position of the reticle stage based on the measured value of the laser interferometer. On the other hand, the wafer W is supported on a wafer holder (not shown) by vacuum suction, and the wafer holder is fixed on the wafer stage 1 movable in the X and Y directions. The wafer stage 1 also includes a stage system for controlling the position and inclination angle of the wafer W in the Z direction. The position of the wafer stage 1 in the X direction and the Y direction is measured with high precision by the movable mirror 8 on the wafer stage 1 and the external laser interferometer 9 and the measured value of the laser interferometer 9 is supplied to the main controller 50. The main controller 50 controls the positioning operation of the wafer stage 1 based on the measured values. The pattern of the reticle R is sequentially transferred to each shot area of the wafer W while the operation of moving the center of each shot area of the wafer W to the exposure center of the projection optical system 10 and the exposure operation are repeated in the step-and-repeat manner by the wafer stage 1 . The main control device 50 is also connected to a console 14 having an input device and a display, and a storage device 13 for storing various parameters.

In addition, a stationary illuminance sensor 7 made of a photodiode or the like is provided near the wafer W on the wafer stage 1. The fixed illuminance sensor 7 in this embodiment is used as a light intensity irregularity measuring sensor of the exposure light IL on the wafer stage 1, a sensor for measuring the maximum illuminance, and a dose amount monitor for measuring the total irradiation amount of the exposure light IL. The light receiving surface of the fixed type roughness sensor 7 is set to be almost the same height as the surface of the wafer W. When the roughness or the irradiation amount in the exposure field of the projection optical system 10 is measured by the fixed type roughness sensor 7, The light receiving unit of the sensor 7 is moved to a desired measurement point. The output signal of the fixed illuminance sensor 7 is supplied to the illumination control unit 12 and A / D converted.

In this embodiment, the integrator sensor 18 and the fixed illuminance sensor 7 in the permanent illuminance sensor are provided. Therefore, when exposure is performed using a plurality of projection exposure apparatuses, it is necessary to calibrate the integrator sensor 18 and the fixed illumination sensor 7 so that the same exposure amount can be set in each projection exposure apparatus.

In order to perform such calibration, a detachable illuminometer 2, which serves as a standard of illuminance, is disposed on the wafer stage 1 so as to be disassembled. That is, when the permanent illuminance sensor is calibrated, the operator mounts the detachable illuminometer 2 on the wafer stage 1. [ At this time, the light receiving surface of the detachable illuminometer 2 is set to be almost the same height as the surface of the wafer W, and the light receiving portion of the detachable illuminometer 2 can be moved in the X and Y directions by driving the wafer stage 1. Further, the removable roughness meter 2 is commonly used for the exposure apparatuses for matching the illuminations between the related exposure apparatuses.

In this case, the projection exposure apparatus mechanism portion of the present embodiment is installed inside the air-conditioned compartment 47, and the control portion such as the roughness control unit 12, the main controller 50, and the console 14 is provided outside the compartment 47. The sensor control device 3 is fixed to the outer surface of the compartment 47 by a magnet book. The detachable illuminometer 2 and the sensor control device 3 are connected via a signal cable 4 passing through the side wall of the compartment 47.

FIG. 2A is an enlarged view showing the detailed structure of the removable roughness meter 2, and FIG. 2B is a plan view of FIG. 2A. 2A and 2B, the detachable illuminometer 2 is constituted by a photoelectric conversion unit 25 and a temperature control element 20 attached thereunder, and is photoelectrically converted to a light quantity incident on a circular light receiving unit 19 on the photoelectric conversion unit 25, The temperature of the photoelectric conversion portion 25 is cooled by the temperature control element 20 so as not to exceed the predetermined allowable temperature. That is, the temperature element 20 is a cooling element such as a Peltier element, and the surface contacting the temperature control element 20 and the photoelectric conversion portion 25 is a cooling surface. Temperature rise of the photoelectric conversion portion 25 due to irradiation energy of the exposure light IL is suppressed by the temperature control element 20, and the change of the sensor characteristic such as sensitivity is reduced.

Power is supplied from the sensor control device 3 through the signal cable 4 to the photoelectric conversion unit 25 and the temperature control device 20, and the output signal from the photoelectric conversion unit 25 is supplied to the sensor control device 3 through the signal cable 4. The detachable illuminometer 2 is fixed on the wafer stage 1 by a fixing fitting 21 and a fixing screw 22 so that the detachable illuminometer 2 can be easily detached from the wafer stage 1 only by disassembling the fixing fitting 21 have. The photoelectric conversion unit 25 also includes a storage unit for storing calibration data for the output of the ambient light sensor, which is a reference higher than the detachable illuminometer 2, as described later.

1, one end of a signal cable 5 for transmitting an output signal supplied from the detachable illuminometer 2 and calibration data is connected to the sensor control device 3, a connector 6 is provided at the other end of the signal cable 5, In the light intensity control unit 12, a connector 11 corresponding to the connector 6 is provided. Then, the connector 6 is fitted into the connector 11 on the side of the illumination control unit 12, the detachable illuminometer 2 and the illumination control unit 12 are connected via the sensor control unit 3, and the output signal of the detachable illuminometer 2 is A / D converted and input to the signal processing unit in the illumination control unit 12 through the input / output control unit such as the GPIB standard or the RS 232C standard incorporated in the signal cable 5, the connectors 6 and 11, and the illumination control unit 12. In the present embodiment, the signal cables 4 and 5, the sensor control device 3, the connectors 6 and 11, and the input / output control unit in the roughness control unit 12 constitute an interface device between the removable roughness meter 2 and the signal processing unit in the roughness control unit 12.

As described above, the output signals of the integrator sensor 18 and the fixed illuminance sensor 7 are also supplied to the illuminance control unit 12. When the permanent illuminance sensor is calibrated, the main illuminator illuminates the detachable illuminometer 2, 7 and the output value of the integrator sensor 18 are subjected to a predetermined calculation in the roughness control unit 12 and the calculation result is supplied to the main controller 50. [ The main controller 50 calculates calibration parameters of the integrator sensor 18 and the fixed illuminance sensor 7 on the basis of the data processed by the illumination control unit 12, and the calculated results are stored in the storage device 13, 14.

Alternatively, the output of the detachable illuminometer 2 may be transmitted to the illumination control unit 12 wirelessly (cordless) as shown in Fig. 2C instead of the wire.

2C shows an example in which an output signal is wirelessly transmitted from a detachable illuminometer. In the detachable illuminometer 2A shown in FIG. 2C, a power supply unit 23 having a storage battery and a wireless transmission paper of its own in addition to the photoelectric conversion unit 25 and the temperature element 20A . Then, the photoelectric conversion unit 25 and the temperature control device 20A are driven using the electric power from the power supply unit 23, and the output signal of the photoelectric conversion unit 25 is transmitted from the antenna 24 connected to the radio transmitter, for example, And a sensor control device 3 having a receiver and an antenna.

In this case, a magnetic chuck is attached to the bottom of the temperature regulating element 20A so as to be easily installed on the wafer stage 1, and a side surface of the temperature regulating element 20A is pressed against the projecting fixing guide 46 provided on the wafer stage 1 It is possible to determine the approximate position of the detachable illuminometer 2A. By attaching the detachable illuminometer 2 A, the sensor controller 3, and further the illuminance control unit 12 shown in FIG. 1 without a code, it is possible to easily attach and detach the removable illuminometer 2 A to the wafer stage 1 in the compartment 47.

1, a focal position detection system of an oblique incidence system composed of a light emitting system and a light receiving system for detecting the position (ultra-low position) of the wafer W in the Z direction is provided on both sides of the projection optical system 10. Information on the focus position of the wafer W from the focus position detection system is supplied to the main controller 50. The main controller 50 controls the focus position and the inclination angle of the wafer W by driving the wafer stage 1 based on the information, W of the projection optical system 10 is aligned with the upper surface (image plane) of the projection optical system 10 to perform exposure.

Next, the basic operation when the illuminance is measured by the detachable illuminometer 2, the integrator sensor 18, and the fixed illuminance sensor 7 of this embodiment will be described. In order to calibrate the output of the integrator sensor 18 and the fixed illuminance sensor 7, a detachable illuminometer 2 is used. To do so, however, it is first necessary to accurately determine the position of the detachable illuminometer 2. The position and measurement of the detachable illuminometer 2 are performed as follows.

3A is an enlarged plan view showing the exposure field EF by the projection optical system 10 on the wafer stage 1 and FIG. 3B is an enlarged plan view showing the exposure field EF. As shown in FIGS. 3A and 3B, The exposure field EF having a substantially square shape is irradiated. 1, the main controller 50 drives the wafer stage 1 based on the positional information of the laser interferometer 9 and, as shown in FIG. 3B, moves the light receiving unit 19 of the removable illuminometer 2 to the exposure field EF In the X direction and the Y direction. Then, the amount of light incident on the light-receiving portion 19 of the detachable illuminometer 2 is sampled at a plurality of predetermined positions through the illuminance control unit 12.

3C shows the relationship between the X coordinate of the wafer stage 1 and the output signal I of the sampled detachable roughness meter 2 when the light receiving unit 19 is scanned in the X direction and the abscissa indicates the X coordinate of the wafer stage 1 and the ordinate indicates the output signal I . As shown in Fig. 3C, the output signal I is large in a range where the light receiving portion 19 is in the exposure field EF, and is small otherwise. Thus, for example, when the output signal I is compared with a predetermined slice level IA between the maximum value and the minimum value of the output signal I, and the output signal I of the wafer stage 1 The X-coordinates X1 and X2 are obtained, and the midpoint coordinate XS of the coordinates X1 and X2 is obtained. The coordinate XS indicates the coordinates of the wafer stage 1 when the center of the light receiving portion 19 of the removable roughness meter 2 is in the center of the exposure field EF (exposure field) of the projection optical system 10.

Accordingly, the relative position in the X direction with respect to the exposure field EF of the projection optical system 10 of the removable roughness meter 2 provided on the wafer stage 1 is obtained. When the illuminance is measured by the detachable illuminometer 2, the automatic focus control is performed so that the top surface of the projection optical system 10 and the surface of the light receiving portion 19 of the detachable illuminometer 2 coincide with each other by the aforementioned focal position detection system of the oblique incidence system. Instead of using such a focal position detecting system, the output signal of Fig. 3C for obtaining the relative position in the X direction may be measured several times while changing the focal position of the light receiving section 19 of the detachable illuminometer 2 to calculate the slope of the slope sections on both sides . The light receiving portion 19 of the detachable illuminometer 2 and the upper surface of the projection optical system 10 can be made to coincide with each other by obtaining the focal position at which the slope of the slope is the highest. Similarly, by scanning the light receiving section 19 in the Y direction with respect to the exposure field EF, the relative position in the Y direction with respect to the field EF of the removable illuminometer 2 is obtained. The relative position of the fixed illuminance sensor 7 to the exposure field EF is obtained in the same manner.

Next, a method of measuring the illuminance by the detachable illuminometer 2, the integrator sensor 18, and the fixed illuminance sensor 7 will be described.

Fig. 4 is a configuration diagram showing the illumination system 17 and the illumination sensor of Fig. 1. As shown in Fig. 4, part of the exposure light IL in the illumination system 17 is received by the integrator sensor 18 in this embodiment. At this time, the light receiving surface of the integrator sensor 18 is almost conjugate with the pattern surface of the reticle R, and moreover, with the surface of the wafer W of Fig.

In this case, since the light collecting lens 43 or the like as the light transmitting portion to the integrator sensor 18 is miniaturized due to restrictions in the arrangement space of the optical member and manufacturing cost, the light receiving portion of the integrator sensor 18 is projected onto the wafer stage 1 As shown in Fig. 5A, the conjugate image 18A is formed with a smaller area than the exposure field EF of the projection optical system 10. [ Therefore, in the integrator sensor 18, it is possible to indirectly measure the illuminance in the range 18A in the conjugate field within the exposure field EF. The center of the conjugate image 18A is set at the center (exposure center) of the exposure field EF. However, if there is a margin in manufacturing cost or the like, the airspace 18A may be larger than the exposure field EF. The light receiving surface of the integrator sensor 18 is not necessarily conjugate with the surface of the wafer W, but may be conjugate with the pupil plane of the projection optical system 10 (optical Fourier transform surface to the reticle R).

5A, the light receiving portion 19 of the detachable illuminometer 2 is formed to have an area smaller than the conjugate image 18A of the light receiving portion of the integrator sensor 18. As shown in Fig. 4, the wafer stage 1 is driven to move the light receiving portion 19 of the removable illuminometer 2 in the exposure field of the projection optical system 10 in order to precisely calibrate the integrator sensor 18 using the detachable illuminometer 2 Thereafter, as shown by the arrow mark in Fig. 5A, the light receiving portion 19 of the detachable illuminometer 2 is moved in the conjugate image 18A to sample the output of the detachable illuminometer 2 at a plurality of predetermined measurement positions. Then, by taking an average value of the output, the average illuminance in the measurement field (interior area of the conjugate image 18A) of the integrator sensor 18 is calculated. In synchronism with the measurement of the detachable illuminometer 2, the output of the integrator sensor 18 is also sampled to calculate an average illuminance. By using such a measurement method, there is an advantage that the measurement field of the integrator sensor 18 and the measurement range of the detachable roughness meter 2 substantially coincide with each other and the reliability of calibration is enhanced.

This measurement method is also performed at the time of measurement of the fixed illuminance sensor 7. 4, when the illuminance is measured by the fixed illuminance sensor 7, the light receiving portion 7A of the fixed illuminance sensor 7 is moved into the exposure field of the projection optical system 10 by driving the wafer stage 1.

5B shows a state in which the light receiving portion 7A of the fixed illuminance sensor 7 is moved in the exposure field EF. As shown in Fig. 5B, the area of the light receiving portion 7A of the fixed illuminance sensor 7 is equal to the area of the light receiving portion 19 of the removable illuminometer 2 Lt; / RTI > 5B, when the output of the integrator sensor 18 and the output of the fixed illuminance sensor 7 are determined, the output of the integrator sensor 18 is compared with the output of the fixed illuminance sensor 7, 7, the light receiving portion 7A of the fixed illuminance sensor 7 is moved more narrowly in the measurement field (inner region of the conjugate image 18A) of the integrator sensor 18, as shown by the arrow in Fig. 5B, Increase the number of samples of illumination. As a result, the measurement field of the integrator sensor 18 and the measurement range of the fixed illuminance sensor 7 substantially coincide with each other. If the areas and shapes of the light receiving portions of the removable roughness meter 2 and the fixed illuminance sensor 7 are made the same, the illuminance can be measured more excellent in the measurement sequence.

The calibration of the output of the integrator sensor 18 and the fixed illuminance sensor 7 is performed by changing the illuminance of the exposure light IL irradiated on the wafer stage 1 stepwise. For example, at the time of calibrating the integrator sensor 18, firstly, the light amount of the exposure light IL from the illumination system 17 is maximized, and the illuminance on the wafer stage 1 is measured. 4, a fourth aperture stop 52D having an opening shown in Fig. 6A is disposed on the exit surface of the fly's eye lens 31, and the aperture of the variable field stop 28 is maximized to obtain a maximum coherence factor (sigma value) The output of the integrator sensor 18 and the output of the detachable illuminometer 2 are simultaneously detected. Subsequently, the σ value is changed stepwise, and the illuminance is measured by the integrator sensor 18 and the removable illuminometer 2 in the same manner. That is, in recent photolithography techniques, for example, a small sigma illumination for illuminating with a small sigma value by using the sixth aperture stop 52F of Fig. 6A, a band-like illumination using a band-like aperture stop such as the third aperture stop 52C And so on. As a result, the calibration result changes depending on the change of the illumination condition. Therefore, it is necessary to perform the same correction even when changing illumination conditions.

6B and 6C show the states of the exposure light on the reticle R under small σ illumination and normal illumination conditions, respectively. As shown in FIGS. 6B and 6C, in the small σ illumination, the opening half angle θ ' Lt; 2 > of the exposure light IL in the illumination condition of the exposure light IL. In general, the sensitivity of the illuminance sensor itself changes according to the incidence angle of the luminous flux, so that the light receiving unit 19 of the removable illuminometer 2, which is the reference of calibration, employs a small change in sensitivity. The integrator sensor 18 uses a temperature sensor or a sensor It is possible to increase the interval for carrying out the calibration for improving the calibration accuracy.

Next, an example of a method of calibrating the output of the integrator sensor 18 and the fixed illuminance sensor 7 using the detachable illuminometer 2 in the projection exposure apparatus of the present embodiment will be described in detail. First, an operator installs a removable illuminometer 2 on the wafer stage 1 of Fig. 1, and connects the signal cable 5 of the sensor control device 3 on the outer surface of the compartment 47 to the illuminance control unit 12. Then, the roughness correction program pre-programmed in the main controller 50 is operated. With the operation of the roughness correction program, the exposure light IL is emitted from the light source unit 16 through the light source control unit 15 under the control of the main controller 50. The exposure light IL is emitted from the projection optical system 10 of the light receiving unit 19 of the removable roughness meter 2 The relative position to the exposure field EF is measured.

Then, based on the measurement result, the center of the light receiving portion 19 of the removable roughness meter 2 is positioned at the exposure center of the projection optical system 10.

In the stepper-type projection exposure apparatus as in the present embodiment, the exposure amount is controlled by using the exposure light IL having a constant roughness and controlling the exposure time on the wafer W by opening and closing the shutter of the light source unit 16. Therefore, after the center of the light receiving section 19 of the removable illuminometer 2 is positioned at the exposure center of the projection optical system 10, the amount of light incident on the integrator sensor 18 is continuously monitored by opening the shutter of the light source section 16, The shutter is closed when the light amount (integrated exposure amount) QI becomes a predetermined value. Then, the illuminance from the opening of the shutter to the closing thereof is measured by the integrator sensor 18 and the detachable illuminometer 2. It is measured by the integrator sensor 18 and the detachable illuminometer 2. The measurement values of the integrator sensor 18 are supplied to the direct illumination control unit 12, and the measured values of the illumination of the removable illuminometer 2 are supplied to the illumination control unit 12 through the sensor control system 3. In the illuminance control unit 12, the integrated light quantity of the integrator sensor 18 and the illuminance integrated value QS in the removable illuminometer 2 are obtained. The cumulative light amount QI by the integrator sensor 18 obtained at this time and the illuminance integrated value QS by the removable illuminometer 2 are denoted by C ₁ and A ₁ , respectively. The illuminance is simultaneously detected by the integrator sensor 18 and the detachable illuminometer 2 while varying the integrated exposure amount in the exposable range and the sum of the integrated amounts C _i (i = 2, 3, ..., n) and the luminance integrated value A _i to the main controller 50. 5, the light receiving portion 19 of the detachable illuminometer 2 may be moved within the conjugate image 18A of the light receiving portion of the integrator sensor 18 at the time of detecting the illuminance.

7A shows the relationship between the accumulated light amount QI in the integrator sensor 18 and the illuminance integrated value QS in the removable illuminometer 2, and as shown by the actual straight line 54 in FIG. 7A, the integrated light amount QS The measured values C ₁ , C ₂ , ... , C _n and the illuminance integrated value QS measured values A ₁ , A ₂ , ... in the detachable illuminometer 2 , And A _n are linear with almost no offset. In the main controller 50, the average value of the output ratio value of the integrator sensor 18 with respect to the output of the detachable illuminometer 2 (hereinafter, referred to as " calibration parameter of the integrator sensor 18 ") P1 is obtained by the following equation.

[Equation 1]

_{P1 = (A 1 / C 1} + A 2 / C 2 + A 3 / C 3 + ... + A n / C n) / n (1)

On the other hand, the calibrating parameters of the fixed illuminance sensor 7 are obtained by using the calibrated integrator sensor 18 as a reference illuminance sensor. That is, the center of the light receiving portion of the fixed illuminance sensor 7 is moved to the exposure center of the projection optical system 10, and the amount of light incident on the integrator sensor 18 and the fixed illuminance sensor 7 is continuously monitored as in the case of the detachable illuminometer 2 . At this time, the light receiving portion of the fixed illuminance sensor 7 may be moved in the conjugate phase of the light receiving portion of the integrator sensor 18. The integrator value of the sensor 18, the integrated light quantity QI of the measurement, where C ₁ with (i = 1, 2, ... , n), and a fixed illumination value of the sensor 7 roughness integrated value QS of B ₁ to be measured correspondingly , There is also a linear relationship with almost no offset as shown by the dotted line 54A in FIG. 7A even between the integrated intensity C ₁ and the integrated luminance value B ₁ . In the main controller 50, an average value (hereinafter referred to as " calibration parameter of the fixed illuminance sensor 7 ") P2 of the output ratio of the fixed illuminance sensor 7 to the output of the integrator sensor 18 at this time is obtained by the following expression.

&Quot; (2) "

_{P2 = (B 1 / C 1} + B 2 / C 2 + B 3 / C 3 + ... + B n / C n) / n (2)

In the case of the stepper-type projection exposure apparatus in which the illuminance of the exposure light is constant, the calibration parameters P1 and P2 are easily calculated and stored in the storage device 13. [ Calibration is performed by multiplying the stored calibration parameters P1 and P2 by the actual measured values of the integrator sensor 18 and the fixed illuminance sensor 7, respectively. That is, by multiplying the measured value of the integrator sensor 18 by the calibration parameter P1, the diffused illuminance is obtained when measurement is performed using the removable roughness meter 2 on the wafer stage 1. Similarly, by multiplying the measured value of the fixed type illuminance sensor 7 by the calibration parameter P2, the illuminance converted into the case of measurement by the integrator sensor 18 is obtained. Further, the products P1 and P2 of the two calibration parameters P1 and P2 may be used as new calibration parameters of the fixed illuminance sensor 7. In this case, by multiplying the measured values of the fixed-type illuminance sensor 7 by the calibration parameters P1 and P2, the illuminance converted into the case of measurement using the detachable illuminometer 2 on the wafer stage 1 is obtained.

When the calibration parameter P1 is obtained as described above, in this embodiment, the output signal of the detachable illuminometer 2 is directly supplied to the illumination control unit 12 through the sensor control device 3 and the signal line 5, and the integrator sensor 18 Is also supplied to the direct illumination control unit 12. Therefore, even if there is a time variation in the output of the exposure light IL from the light source unit 16 due to arc fluctuation of the mercury lamp, the output signals of the integrator sensor 18 and the removable roughness meter 2 are inputted at the same timing, The parameter P1 can be accurately obtained, and the calibration of the integrator sensor 18 can be made with high accuracy. In addition, when the calibration parameters P1 and P2 are used, the fixed illuminance sensor 7 can be calibrated with high precision with respect to the removable illuminometer 2. In the present embodiment, since the measurement values of the detachable illuminometer 2, the integrator sensor 18, and the fixed illuminance sensor 7 are commonly inputted in the illuminance control unit 12, the arithmetic processing of the expressions (1) and (2) .

When the projection exposure apparatus of FIG. 1 is of the scanning exposure type such as the step-and-scan method, the output of the integrator sensor 18 and the fixed illuminance sensor 7 are detected by using the detachable illuminometer 2 Describe how to calibrate.

In the scanning exposure type projection exposure apparatus, during exposure, the exposure light IL from the light source unit 16 is irradiated onto the illumination area on the slit on the reticle R. Then, the reticle R and the wafer W are synchronously scanned with respect to the projection optical system 10 in a state in which the pattern in the illumination area on the reticle R on the reticle R is projected onto the wafer W through the projection optical system 10 so that the pattern image of the reticle R is projected onto the wafer W As shown in FIG. Since the exposure is continuously performed in the scan exposure type, whether or not the illuminance of the exposure light measured by the integrator sensor 18 is always within the permissible range with respect to the predetermined target value, instead of monitoring the accumulated light amount of the output value of the integrator sensor 18 Monitored. In this case, the width (slit width) in the scanning direction of the exposure area obtained by projecting the sensitivity (the appropriate exposure amount) of the photoresist on the wafer W, the scanning speed of the wafer stage 1 to V, and the slit- , And the illuminance of the exposure light IL on the wafer W is S, the following relationship is established.

&Quot; (3) "

E / S = L / V (3)

In order not to lower the throughput of the exposure process, it is preferable to scan the wafer W at the highest speed as possible. Therefore, the scanning speed V is usually set near the maximum speed. Assuming that the slit width L is set near the maximum width, the right side of the equation (3) is almost constant. Therefore, when the sensitivity E of the photoresist is different depending on the layer or the like on the wafer W, it is necessary to change the illuminance S of the exposure light IL corresponding to the sensitivity E in order to satisfy the expression (3). When the illuminance S is changed, for example, a photosensitive mechanism capable of continuously varying the light amount of the exposure light stepwise and within a predetermined range is provided in the light source unit 16, or a variable power source for controlling the driving power of the exposure light source in the light source unit 16 And the photosensitive device or the variable power source may be used. When the illuminance S of the exposure light IL is changed in this way, the relationship of the output of the integrator sensor 18 with respect to the output of the detachable illuminometer 2 may change slightly.

Therefore, in the scanning exposure projection exposure apparatus, the illuminance of the exposure light IL is measured by the integrator sensor 18 and the removable roughness meter 2 while changing the illuminance S of the exposure light IL through the photosensitive mechanism or the variable current source. At this time, the illuminance LI measured by the integrator sensor 18 is referred to as c _i (i = 1, 2, 3, ..., n). At the same time, the illuminance LS measured by the detachable illuminometer 2 is a _i .

7B shows the relationship between the illuminance LS measured by the detachable illuminometer 2 and the illuminance LI measured by the integrator sensor 18. When the illuminance LS and the illuminance LI have good linearity, Likewise, in the integrator sensor 18, the measured values of illumination LI, c _i , c ₂ , ... c _n , the measured values of the illuminance LS in the detachable illuminometer 2, a ₁ , a ₂ , ... The relationship of a _n is a straight line with almost no offset. In this case, the average value of the measured values a _i / c _i of the obtained illuminance can be used as a calibration parameter. However, when the linearity between the two roughnesses is poor, a single calibration parameter P1 is determined as in a stepper-type projection exposure apparatus, and correction based on the one calibration parameter P1 increases the measurement error of roughness.

Therefore, when the linearity between the two roughnesses is poor in the scan exposure type, the ratio a ₁ / c ₁ , a ₂ / c ₁ of the measured value c _i of the illuminance LI of the integrator sensor 18 to the actual value a _i of the roughness LS of the removable roughness meter 2, c ₂ , a ₃ / c ₃ , ... , a _n / c _n are calculated, and the obtained value a _i / c _i is approximated by a curve. That is, as one example, in the main controller 50, the obtained value a _i / c _i is converted to a function f (LI) of the m-th order (m is an integer of 2 or more) with respect to the illuminance LI measured by the integrator sensor 18 And the coefficient of each order of the function f (LI) is obtained and stored in the storage device 13 as a calibration parameter. As a result, the illuminance LS measured by the detachable illuminometer 2 is represented by the following equation.

&Quot; (4) "

LS = f (LI) · LI (4)

Then, by multiplying the illuminance L1 measured by the integrator sensor 18 by the function f (L1) at the time of exposure, the illuminance converted into the illuminance LS measured using the removable illuminometer 2 on the wafer stage 1 is obtained.

Further, instead of performing the curve approximation, the value a _i / c _i of the obtained ratio may be stored in a table related to illumination LI. At this time, for example, between the measured values c _{i to} c _i +1 of the illuminance of the integrator sensor 18, the ratio LS / LI by the proportional distribution is calculated and the output of the integrator sensor 18 is corrected good.

Also in the case of the scan exposure type, the calibration parameters of the fixed illuminance sensor 7 can be obtained by using the calibrated integrator sensor 18. That is, by using the measured value c _i of the illuminance LI of the integrator sensor 18 measured while varying the illuminance of the exposure type and the measured value b _i of the illuminance (denoted by LS ') of the fixed illuminance sensor 7 measured corresponding thereto, If the linearity is good to the average value of the measured values c _i and b _i, so in the linear relationship even almost no offset as shown in 7b dotted line 55A between the ratio values of their measured values c _i / b _i into calibration parameters have. However, when the linearity of the both is bad, the value c _i / b _i may be approximated by a higher function g (LS ') of the illuminance LS' of the fixed illuminance sensor 7 or may be tabulated.

By calculating the calibration parameters in this manner, the output of the integrator sensor 18 and the removable illuminometer 2 can be calibrated with high precision even in the case of the scanning type exposure type. Since the output signals of the integrator sensor 18 and the removable illuminometer 2 can take the same timing, the calibration parameters can be accurately obtained, and the calibration of the integrator sensor 18 and the fixed illuminance sensor 7 can be performed with high accuracy .

Also, in the case of the stair-type projection exposure apparatus, when the illuminance of the exposure light is changed, the relationship between the output of the integrator sensor 18 and the output of the removable roughness meter 2 is approximated by a function of the second order or more, It may be stored as a parameter. The same is true for the fixed illuminance sensor 7.

Next, a second embodiment of the present invention will be described with reference to Figs. 8 and 9. Fig. In this embodiment, the present invention is applied to a stator-type projection exposure apparatus using a pulsed light source as an exposure light source, and the same reference numerals are applied to parts corresponding to those in Figs. 1 and 4, and detailed description thereof is omitted.

8 is a schematic configuration diagram showing the projection exposure apparatus of this embodiment. In the light source unit 16A of FIG. 8, an excimer laser light source 40 made of an ArF excimer laser light source or a KrF excimer laser light source is used as an exposure light source for pulsed light emission. The light emission operation of the excimer laser light source 40 is controlled by the main controller 50 through the laser controller 41 in the light source control unit 15A. The timing of the pulse light emission of the excimer laser light source 40, the oscillation frequency, Control and the like are performed.

The exposure light ILA, which is laser light emitted from the excimer laser light source 40, passes through a pair of variable ND filters 38A and 38B arranged around only a beam expander 39 and an ND filter of various transmittances. By adjusting the combination of the ND filters of the variable ND filters 38A and 38B through the driving unit 38C, the photosensitivity for the exposure light ILA can be changed over a multistage. The operation of the driving unit 38C is configured so that the main controller 50 can be controlled through the light-sensing unit control system 42 in the light source control unit 15A. The exposure light ILA having passed through the variable ND filters 38A and 38B enters the illumination system 17A and passes through the first fly's eye lens 37, the relay lens 36, the speckle removal drive mirror 35 and the second fly's eye lens 31, And enters the splitter 33.

A part of the exposure light ILA separated by the beam splitter 33 is incident on the integrator sensor 18 via the condenser lens 43. On the other hand, the exposure light ILA transmitted through the beam splitter 33 illuminates the reticle R through an optical system 34 including a variable field stop, a condenser lens, and the like. During measurement of the illuminance, the exposure light ILA transmitted through the reticle R is incident on the detachable illuminometer 1 provided with the wafer stage 1 through the projection optical system 10. The output of the detachable illuminometer 2 is supplied to the illuminance control unit 12 on-line via the signal lines 4 and 5, the sensor control unit 3 and the connector not shown. A fixed illuminance sensor 7 is also fixed on the wafer stage 1, and the outputs of the integrator sensor 18 and the fixed illuminance sensor 7 are supplied to the illuminance sensor unit 12. The other configurations are the same as those of the projection exposure apparatus shown in Fig.

In this case, since the illuminance (pulse energy) of each pulse is unstable in the excimer laser light source, exposure light of, for example, several tens of pulses is irradiated at each point on the wafer, and the uniformity . That is, in the projection exposure apparatus of Fig. 8, the minimum number of pulses of the exposure light ILA for each point on the wafer is determined. For example, when the oscillation frequency of the excimer laser light source 40 is 500 Hz, the arbitrary nonuniformity of the illuminance per pulse is 5%, and the number of exposure pulses is 50 pulses, the unevenness of the integrated exposure amount on the wafer after 50 pulse exposure is About 0.7%, and the exposure time is 0.1 second.

In this embodiment, the illuminance of the exposure light ILA can be changed step by step by the combination of the variable ND filters 38A and 38B as the light-sensitive portions, and the output of the excimer laser light source 40 can be continuously changed through the laser control device 41 Consists of. Therefore, in the step-type projection exposure apparatus using the pulse light source as in the present embodiment, a pulse is generated for a predetermined time in the excimer laser light source 40 without controlling the exposure amount by the shutter, and the control of the integrated exposure amount The illuminance of the exposure light ILA is continuously changed. That is, when the sensitivity of the photoresist on the wafer is E, the energy of one pulse of the exposure light ILA is p, and the number of exposure pulses is n on the wafer, the following relationship holds.

&Quot; (5) "

E = np (5)

Thus, when the sensitivity E of the photoresist changes, the amount of light is changed stepwise by the combination of transmittances of the variable ND filters 38A and 38B, and the output of the excimer laser light source 40 is fine-tuned by the laser control device 41, The energy p of one pulse is continuously controlled. At the time of exposure, the energy p for each one pulse is measured by the integrator sensor 18, and the excimer laser light source 40 and the variable ND filters 38A and 38B are controlled on the basis of the energy p.

Next, a method of calibrating the output of the integrator sensor 18 using the detachable illuminometer 2 in the present embodiment will be described in detail. First, the light receiving portion of the detachable light illuminometer 2 is moved into the conjugate phase of the light receiving portion of the integrator sensor 18, the energy p of one pulse is set to be, and the excimer laser light source 40 is pulsed.

9A shows timing of pulse light emission in the excimer laser light source 40. The abscissa axis indicates time t and the ordinate axis indicates a flag FA that becomes a high level '1' at the time of pulse generation. As shown in Fig. 9A, first, pulse generation is performed in a false state without performing measurement for a predetermined time TD after the time tS, and n pulses are generated for measurement within the measurement time TM between the times t1 and t2 do.

FIG. 9B shows a flag FB which becomes a high level '1' during a period of measurement by the integrator sensor 18, FIG. 9C shows a flag FC which becomes a high level '1' during a period of measurement by the detachable illuminometer 2, As shown by the flags FB and FC, the measurement is simultaneously performed between the time t1 and the time t2 in the integrator sensor 18 and the removable roughness meter 2. In the roughness control unit 12, the peak hold value of the output of the integrator sensor 18 is taken for each pulse generation. In the sensor control device 3, the peak hold value of the output of the removable roughness meter 2 is A / And supplies it to the unit 12. The thus measured values are referred to for convenience as the illuminance of each pulse light.

In this case, the illuminance of each pulse measured by the integrator sensor 18 and the detachable illuminometer 2 is assumed to be d _i , e _i (i = 1, 2, 3, ..., n). If the relationship between the illuminance d _i and e _i is close to linear, a constant calibration parameter is obtained and stored in the same manner as in equation (1). On the other hand, when the relation between the illuminance d _i and e _i is nonlinear, the relationship between the illuminance d _i and e _i is obtained by a method of a least squares method or the like, and the function is stored as a calibration parameter. Alternatively, the relationship between illuminance d _i and e _i may be tabulated and stored.

Subsequently, the calibrated integrator sensor 18 is used as a reference illuminance sensor to obtain a fixed parameter of the fixed illuminance sensor 7. That is, the light receiving portion of the fixed illuminance sensor 7 is moved in the conjugate phase of the light receiving portion of the integrator sensor 18, and the excimer laser light source 40 is pulsed as in the case of the above-described detachable illuminometer 2, 7 to measure the illuminance. The illuminance of each of the integrator sensor 18 and the fixed illuminance sensor 7 measured here is denoted by d _i and f _i (i = 1, 2, 3, ... n). If the relationship between illuminance d _i and f _i is close to linear, a certain calibration parameter is obtained in the same manner as in equation (2). If the relationship between illuminance d _i and f _i is nonlinear, the relationship between illuminance d _i and f _i is determined by function or table type. At the time of actual exposure, the calibrated illuminance is detected by multiplying the measured values of the integrator sensor 18 and the fixed illuminance sensor 7 by the calibration parameters thus obtained.

Even if the output of the exposure light ILA from the light source unit 16A varies temporally, the integrator sensor 18 and the fixed illuminance sensor 7 for the detachable illuminometer 2, Can be precisely corrected. Further, since the measurement values of the integrator sensor 18 and the like of the removable illuminometer 2 are commonly applied to the illuminance control unit 12, the arithmetic processing for obtaining the calibration parameters can be performed at high speed.

Next, an example of a method of managing the detachable illuminometer 2 used in the above-described embodiment will be described with reference to Figs. 10 and 11. Fig. The removable illuminometer 2 of FIG. 1 is used as a reference illuminance sensor for a plurality of exposure apparatuses (for example, 10 magnifications) to be matched. That is, the attaching and detaching type roughness meter 2 is installed in an exposure apparatus requiring roughness correction, and the detachment type roughness meter 2 is removed from the exposure light source after the roughness calibration work is finished, and the operation of using it for calibration of another exposure apparatus is repeated. For example, in the projection exposure apparatus of Fig. 1 where the illuminance is corrected by the removable illuminometer 2, the integrator sensor 18 of the projection exposure apparatus itself becomes the reference illuminometer after that. However, since the integrator sensor 18 is always irradiated with the exposure light, its sensitivity characteristic changes with time. For example, if the sensitivity characteristic is stable for about 3-6 months, and the change does not occur, the intensifier sensor 18 may be used as the reference illuminance sensor as it is within the period of time. However, It is preferable to correct the intensities of the integrator sensor 18 with a properly stored reference illuminance sensor (reference illuminance sensor).

In this case, it is physically difficult to manage illumination with only one reference illuminance sensor if the number of matching exposure apparatuses increases, and the reference illuminance sensor may also fail. Thus, a plurality of reference instruments each having a plurality of standard illuminance sensors, for example, reference illuminance sensors of about one to three generations are used as mosquitoes and are calibrated by the respective mosquitoes, It is preferable that the management structure is provided by a metrology structure having a plurality of grandchildren each corrected by a plurality of grandchildren.

10A shows an example of the management system of the reference illuminance sensor. In FIG. 10A, three magnets B1-B3 are calibrated for one atmospheric mosquito A1, and a plurality of magnets C1-Cn, D1 to Dj, E1 to Em are corrected. A reference illuminance sensor such as the removable illuminometer 2 of Fig. 1 is used for the mosquito A1, magnetic B1-B3, and claw C1-Cn. By taking such a management system of the reference illuminance sensor, it is possible to appropriately calibrate the illuminance sensors of a plurality of exposure apparatuses. Since the mosquito A1 is a reference of the reference illuminance sensor, it is preferable that the mosquito A1 is excellent in the linearity and stability of the sensitivity characteristic to the incident light quantity. For example, when calibrating the outputs of the magnets B1-B3 with respect to the mosquito A1, for example, the illuminance of the exposure light may be alternately measured by the mosquito A1 and magnets B1-B3, or the exposure light may be divided into two The illuminance is simultaneously measured in the mother A1 and the magnets B1-B3, and the value of the ratio at the time of measurement is obtained.

10B shows a case in which the linearity of the measured value of the mother A1 and the linearity of the measured values of the magnets B1 to B3 is good. The abscissa of FIG. 10B shows the light amount (illumination) x of the exposure light incident on the reference illuminance sensor, The ratio of the measured values of B1 to B3 (measurement ratio) y. In this case, as shown by the straight line 56, the light quantity x and the measurement ratio y are expressed by a linear function of (y = ax + b) using the coefficients a and b. Therefore, the magnets B1-B3 are provided with a storage section for storing the coefficients a and b, and these coefficients a and b are supplied to the sensor control apparatus 3 of Fig. 1 as the measured values of the actual roughness, The measured values of B1-B3 may be calibrated.

When the relationship between the measured value of the mosquito A1 and the measured value of the magnets B1 to B3 is nonlinear, the relationship of the measurement ratio y with respect to the light quantity x is a function of higher order (y = f (x) ). At this time, data in which the coefficients of the function f (x) are stored in the storage unit of the magnets B1-B3 or the relationship between the light quantity x and the measurement ratio y is stored in the storage unit, . When calculating the measurement ratio y in this manner, the calculation as described in Fig. 7B may be used.

Next, for example, when calibrating the outputs of the hands C1 to Cn with respect to FIG. 10A and the magnetic B1, it is necessary to obtain the measurement ratios of both of them and store the coefficient or function indicating the measurement ratio in the storage unit of the hands C1 to Cn good. Similarly, the output of the lower hand corresponding to each of the other magnets B2 and B3 is also corrected.

Here, the calibration method between these reference illuminance sensors will be described in detail. As one example, the case of calibrating the output of the removable illuminometer 2 of Fig. 1 for the mosquito A1 will be described. There are two methods of this calibration method: a method of measuring the illuminance of two reference illuminance sensors at the position of the integrator sensor 18; and a method of measuring the illuminance of the two reference illuminance sensors on the wiper stage 1. For this reason, a calibration jig having a beam splitter that accommodates two reference illuminance sensors and divides the exposure light into two is used.

Fig. 11A is a sectional view of the calibration jig 44 for measuring the illuminance with two reference illuminance sensors at the position of the integrator sensor 18 in Fig. 4. When the calibration is performed, the integrator sensor 18 and the condenser The lens 43 is removed and the calibration jig 44 is disposed instead. The exposure light separated by the beam splitter 33 in the illumination system 17 of FIG. 4 is incident on the beam splitter 58 via the condenser lens 43A in the calibration jig 44 of FIG. 11A, and the incident exposure light IL is converted into two light beams by the beam splitter 58 . In the calibration jig 44, a mosquito A1 and a removable illuminometer 2, which are opposed to the two emitting surfaces of the beam splitter 58, are fixed. The light flux transmitted through the beam splitter 58 is incident on the modi A1, and the light flux reflected by the beam splitter 58 is incident on the detachable illuminometer 2. The output signals from the mosquito A1 and the removable roughness meter 2 are sent to the signal processing system 59. In the signal processing system 59, for example, as shown in Fig. 7B, the output signal from the removable roughness meter 2 A function or a table showing the ratio of the measured illuminance (calibration parameter) or the ratio thereof is obtained. The calibration parameters or functions thus obtained are sent to the host computer 60, stored therein, and stored in the storage unit in the removable illuminometer 2.

11B shows a cross-sectional view of the calibration jig 45 for calibrating the removable roughness meter 2 by the mosquito A1 on the wafer stage 1. As shown in Fig. 11B, the calibration member 45 is placed on the upper surface outer edge of the wafer stage 1 Fixed. In the calibration jig 45, a relay lens 61, a beam splitter 62, and relay lenses 63A and 63B for collecting the light flux from the beam splitter 62, which make the exposure light IL from the projection optical system 10 into a parallel light flux, are provided. The mosquito A1 and the detachable illuminometer 2 are fixed so as to be opposed to each other. When calibrating, the wafer stage 1 is driven to align the optical axes of the relay lenses 61 and 63A with the exposure center of the projection optical system 10.

The exposure light IL from the projection optical system 10 passes through the relay lens 61, becomes a parallel light flux, enters the beam splitter 62, and is split into two light fluxes by the beam splitter 62. The light flux transmitted through the beam spiller 62 is incident on the mosquito A1 through the relay lens 63A, and the light flux reflected by the beam spiller 62 is incident on the detachable illuminometer 2 via the relay lens 63B. The output signals from the mosquito A1 and the detachable roughness meter 2 are sent to the signal processing system 59. In the signal processing system 59, the calibration parameters of the detachable roughness meter 2 or the calibration function and the like are obtained as described with reference to Fig. The calibration parameters or functions thus obtained are stored in the host computer 60 and also stored in the storage unit of the removable illuminometer 2.

The roughness matching between the respective exposure apparatuses is performed by the reference illuminance sensor corrected by the above-described method. However, in order to satisfy the accuracy of, for example, 1.4% or less, the detachable illuminometer 2 and the integrator sensor 18 Measurement characteristics are set so as to satisfy the following allowable values.

A. Removable Roughness Tester 2

(a) Measurement reproducibility (measurement reproducibility): ± 0.07 (%) (Lee, Seung Hwa,

(b) Measurement straight type (after soft correction): ± 0.07 (%) (Simplified, simple sum)

(c) Angular characteristic train (angle characteristic difference): ± 0.1 (%) (simplified)

(d) Stability (24 hours total): ± 0.25 (%) (simplified)

B. Integrator Sensor 18

(a) Measurement reproducibility: ± 0.05 (%) (Lee Seung Hwa)

(b) Measurement linearity (after soft correction): ± 0.05 (%) (Simplified)

(c) Angular characteristic Train: ± 0.1 (%) (simplified)

(d) Stability (total investigation time): ± 0.25 (%) (simplified)

Among the above items, the measurement linearity represents the linearity of the output with respect to the incident light amount, and the angular characteristic train represents the variation of the output change when the opening angle (coherence factor) of the exposure amount is different. The calibration for the integrator sensor 18 and the fixed illuminance sensor 7 in each of the exposure apparatuses is carried out every time the exposure light source (mercury lamp or the like) is replaced by using the detachment type illuminometer 2 as described above. The time required for the measurement is 0.2 hours, The number of exposure apparatuses managed by one detachable illuminometer 2 is 20, and the calibration interval of the detachable illuminometer 2 itself is 6 months.

For example, when calculating the matching accuracy MS between the exposure apparatuses of the illuminance measured by the integrator sensor 18 of this embodiment, when the reference detachable illuminometer 2 is, for example, the self B1 of FIG. 10A, Since the measurement errors of two of them are overlapped, the measurement characteristics are as follows.

MS = (0.07 ² x 2 + 0.05 ² ) ^1/2 + 0.07 x 2 + 0.05 + 0.1 x 3 + 0.25 x 3? 1.35 (%)

Therefore, the value of the matching precision MS becomes smaller than 1.4% of the allowable range, and the illuminance is measured with high matching precision.

Each reference illuminance sensor described above is not a sensor for measuring an absolute light amount including a mosquito but is a sensor for measuring a relative amount of light by considering the mosquito as the best reference, that is, the illuminance measured with a mosquito as a kind of absolute light amount reference. However, when the i-line or the like of the mercury lamp is used as the exposure light, it is difficult to control the absolute amount of light because the illumination brightness is high and it is difficult to produce parallel rays. In addition, although the difference in angular characteristic period is described in the measurement characteristic, there are two reasons for requiring a small angular characteristic phase difference in the following C1 and C2.

C1. There are two types of errors due to the angular characteristics of the illuminance sensor, such as the detachable illuminometer 2 and the integrator sensor 18. The first error is an error that occurs in principle in proportion to the cosine of the incident angle due to Lambert's law when the illumination field is larger than the light receiving field of the illuminance sensor. However, when the light receiving surface of the light intensity sensor is at the image forming position, there is no problem. However, when the light receiving surface is defocused, an error such as " This error is referred to as " error due to light receiving field characteristics ".

The second error is caused by coating or the like on the detection surface of the illuminance sensor. Which is an error due to a change in sensitivity depending on the incident angle of the exposure light. This is referred to as " error due to detector angle characteristic ".

If there is a difference in angular characteristic due to the difference in the illuminance sensor, that is, if there is an error in the angular characteristic, accurate comparison of the relative light quantity can not be made when the incident angle of the exposure light changes due to, for example, deformation illumination. However, when the appropriate exposure dose (dose) is set, the characteristics of the photoresist also become a factor. In addition, since dose setting is performed in both normal illumination and deformation illumination, the absolute value of the absolute angle No characteristics are required. However, when roughness matching for a plurality of exposure apparatuses is considered, the angular characteristic is a factor of a large measurement error. Therefore, it is necessary to reduce the angular characteristic trains of the detachable illuminometer 2 and the integrator sensor 18. In this respect, the value of the angle characteristic train is set by assuming the most difficult lighting condition that a band-shaped illumination is used and a band having a light-shielding ratio of 2/3 of the outer diameter of the opening is used as an aperture stop of the illumination system .

C2. In the case of the fixed illuminance sensor 7, as an example, when there is a difference in sigma value (numerical aperture) depending on the image height in order to measure the relative illuminance unevenness in the exposure field, when the error due to the detector angle characteristic is large, The difference in the sigma value of the line width is not detected, and thus a line width error occurs. On the other hand, when the error due to the detector angle characteristic is small, it becomes possible to manage the line width error by the difference of the sigma value.

In the above-described embodiments, the reference illuminance sensor is studied for a stepper-type exposure apparatus and a scanning exposure type projection exposure apparatus, respectively. However, when the same exposure light source is used, it is necessary to match also between exposure apparatuses of different systems. Therefore, the removable illuminometer 2 can cope with both of the correction methods shown in Figs. 7A and 7B so that the stabbing type exposure apparatus and the scanning exposure type exposure apparatus are all matched. In this case, since the shape of the exposure field is different by the exposure apparatus, it is preferable that the shape of the light receiving unit of the detachable illuminometer 2 is made common or only the light receiving unit (probe unit) of the detachable illuminometer 2 is replaceable.

As described above, according to the above embodiment, a plurality of reference illuminance sensors (detachable illuminometer 2) are managed in a hierarchical structure of mosquitoes, magnetism, and tactile sense, and reference illuminance sensors other than a mosquito And the calibration parameters or correction relational expressions are stored. Therefore, all the lower reference illuminance sensors measure the relative illuminance on the basis of one mosquito, and even when a plurality of exposure apparatuses are used, the matching accuracy of the measured values of the illuminance between the exposure apparatuses is improved. In addition, even if a reference illuminance sensor temporarily fails, it can be replaced with another reference illuminance sensor.

In the above-described embodiment, the detachable illuminometer 2 is detachably mounted on the wafer stage 1 by an operator, but a transport device for transporting the detachable illuminometer 2 is provided, the wafer stage 1 is retracted, and the detachable illuminometer 2 Or may be moved to the exposure center or the like of the projection optical system 10 to measure the illuminance. Alternatively, the detachable illuminometer 2 may be disposed between the projection optical system 10 and the wafer W by a slider for carrying the wafer. In these methods, it is not necessary for the operator to enter the compartment 47, and the calibration operation of the illuminance sensor can be performed more quickly.

The present invention is not limited to the above-described embodiments, and various configurations can be adopted without departing from the gist of the present invention.

According to the first exposure apparatus of the present invention, an interface device for inputting measurement data of the detachable illuminance sensor is provided, and the relationship between the output of the permanent illuminance sensor and the output of the detachable illuminance sensor is obtained and stored in the exposure amount control means. Since the measurement data of the two light intensity sensors are input at almost the same time by the interface device, the output ratio of the light intensity sensor can be obtained accurately even if the output of the exposure light source has time fluctuation due to unevenness such as arc fluctuation or pulse energy, There is an advantage that the calibration can be precisely performed.

At this time, since the measurement data of the bidimensional sensor is commonly processed by the exposure amount control means, the processing of the measurement data can be performed at a high speed. In addition, an input error due to operator intervention does not occur.

The indirect illumination sensor (for example, an integrator sensor) indirectly measures the illuminance of the illumination light on the substrate stage by detecting the illuminance of the light flux separated from the illumination light, and the exposure amount control means When the measurement data of the permanent illuminance sensor is input in synchronization with the input of the measurement data of the detachable light intensity sensor through the interface device, the measurement data of the two most of the light intensity sensors are taken at the same timing, The calibration accuracy of the permanent illuminance sensor in the case of fluctuation can be increased.

In the case where the illumination light for exposure is pulsed light emission and the exposure amount control means inputs the measurement data of the detachable illuminance sensor through the interface device in synchronism with the pulse light emission for the exposure illumination light, So that the illumination can be precisely measured without deviating from the measurement timing of the detachable illuminance sensor and the permanent illuminance sensor, and the output of the permanent illuminance sensor can be accurately calibrated.

In addition, when the interface device supplies the measurement data of the detachable illuminance sensor to the exposure amount control means in a cordless manner, there is an advantage that the work for attaching and detaching the detachable illuminance sensor onto the substrate stage is facilitated.

Further, according to the second exposure apparatus of the present invention, in the case of performing illumination correction of a plurality of exposure apparatuses, the second detachable illuminance sensor is used as a mother machine and the first detachable illuminance sensor is used as a self- It is possible to precisely calibrate its output. Therefore, there is an advantage that the accuracy of roughness matching between a plurality of exposure apparatuses is improved. Further, by providing a plurality of magnets for the mosquito and by providing a plurality of grandchildren for the magnets, it is possible to improve the accuracy of roughness matching between more exposure apparatuses, and even when a detachable illuminance sensor fails Other detachable illuminance sensors can be substituted.

Further, according to the third exposure apparatus of the present invention, the illuminance of the illumination light divided by the division optical system on the substrate stage can be measured by the first and second detachable illuminance sensors and the first detachable illuminance sensor can be calibrated, There is no influence by the shaking of the illumination light or the optical system in the middle, and there is an advantage that the first illuminance sensor is precisely corrected. Therefore, the accuracy of matching between the exposure apparatuses is improved.

Claims (6)

An exposure apparatus which has a substrate stage for determining the position of a photosensitive substrate and transfers a pattern formed on a mask under illumination light for exposure onto the photosensitive substrate on the substrate stage, A detachable illuminance sensor detachably mounted on the substrate stage for directly measuring illuminance of the illumination light on the substrate stage, A permanent illuminance sensor for directly or indirectly measuring illuminance of the illumination light on the substrate stage, An interface device for receiving measurement data of the detachable illuminance sensor, And an exposure amount control means for obtaining and storing the relationship between the measurement data of the detachable illuminance sensor input through the interface device and the measurement data of the permanent illuminance sensor. The method according to claim 1, The permanent illuminance sensor is an indirect type ambient light sensor that indirectly measures the illuminance of the illumination light on the substrate stage by detecting the illuminance of the light flux separated from the illumination light, Wherein the exposure amount control means receives the measurement data of the detachable illuminance sensor through the interface device and the measurement data of the permanent illuminance sensor synchronously. 3. The method according to claim 1 or 2, The illumination light for exposure is an illumination light that is pulsed, Wherein the exposure amount control means receives the measurement data of the detachable illuminance sensor via the interface device in synchronization with the pulse light emission of the exposure amount illumination light. The method according to claim 1, 2, or 3, Wherein the interface device supplies measurement data of the detachable light intensity sensor to the exposure amount control means in a cordless manner. 1. An exposure apparatus which has a substrate stage for determining the position of a photosensitive substrate and transfers a pattern formed on a mask under exposure illumination light to a photosensitive substrate of the substrate stage, A permanent illumination sensor for directly or indirectly measuring the illuminance of the illumination light on the substrate stage, A first detachable illuminance sensor detachably mounted on the substrate stage for directly measuring the illuminance of the illumination light on the substrate stage for calibrating the output of the permanent illuminance sensor, And storage means for storing a correction value of the output of the first detachable illuminance sensor with respect to an output of the second detachable lightness sensor as a predetermined reference. 1. An exposure apparatus which has a substrate stage for determining the position of a photosensitive substrate and transfers a pattern formed on a mask under illumination light for exposure onto a photosensitive substrate on the substrate stage, A permanent illuminance sensor for directly or indirectly measuring illuminance of the illumination light on the substrate stage, A first detachable illuminance sensor detachably mounted on the substrate stage for directly measuring the illuminance of the illumination light on the substrate stage for calibrating the output of the permanent illuminance sensor, A second detachable illuminance sensor serving as a reference of the output of the first detachable illuminance sensor, A division optical system for dividing the illumination light for exposure on the substrate stage and guiding the illumination light to the first and second detachable lightness sensors, And a signal processing device for receiving and comparing outputs of the first and second detachable light intensity sensors in parallel.